There is known a conventional apparatus that detects an obstacle located at a blind spot of a driver by using an obstacle sensor mounted on a vehicle and notifies a driver of the detected obstacle. When detecting an obstacle, the apparatus notifies the driver of the obstacle by performing display switching (see Japanese Laid-open Patent Publication No. 2013-190957, for example).
However, when display switching is performed every time an obstacle is detected like the conventional apparatus, the apparatus notifies a driver of an obstacle even when it is not required that the driver is notified of the obstacle. As described above, the conventional apparatus cannot appropriately notify a driver of an obstacle in some cases.